The use of sophisticated component placement machines in manufacturing printed circuit or similar cards, boards, panels, and the like is well known. The term printed circuit board (PCB) as used herein refers to any such electronic packaging structure. Typically, components are supplied to the placement machine by a variety of feeders. Examples of feeders include tape feeders which hold one or more reels of components, matrix feeders which hold one or more pallets of components, and wafer feeders which hold one or more wafers of dies. All of these feeders provide components at a pick station of some type. A housing carrying a rotatable frame having a plurality of pick and place heads, each pick and place head having a vacuum spindle equipped with a nozzle, may be moved in the X and Y axes in a plane above the PCB being populated. Each vacuum spindle may be moved in the Z-axis (i.e., in and out from an extended to a retracted position). Each nozzle is sized and otherwise configured for use with each different size and style of component to be placed by the machine.
In operation, the housing carrying the rotatable frame is moved to the feeder pick station and the nozzle of one of the pick/place heads is positioned over the component. The nozzle is lowered, via its associated vacuum spindle (i.e., extended) to a point where, upon application of vacuum, the component is removed from the feeder, and held tightly against the vacuum nozzle orifice. The rotatable frame is then moved to a point over the PCB being assembled. The vacuum spindle is then lowered and the component is deposited on the PCB at a predetermined location.
For some processes a component may need to have a fluid, such as flux, an adhesive, or the like, applied prior to placement on the PCB. In this case, the rotatable frame will first move to a fluid application station located in the machine and then extends the spindle such that the fluid is applied to the bottom of the component. Once the fluid is applied, the spindle is raised and the rotatable frame is moved to the PCB. With multi-pick and place head machines, the need to apply fluids to components efficiently to improve cycle rate has become more critical.
In the past, when the nozzle of a particular pick and place head carried a component requiring a fluid be applied, the entire housing and rotatable frame had to be moved in the X-Y plane to a designated fluid application station to apply the fluid to the component. Needless to say, as the entire multi-head rotatable frame needed to move, all other pick/place heads thereupon were prevented from picking and placing components during the trip to the fluid application station. This resulted in lower placement machine throughput because of this motion as would be true even for single pick/place heads.